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What Causes Bipolar Disorder in Children

Updated on March 6, 2012

Bipolar disorder in children appears to be on the rise in recent decades. Since the late 1990s, the rate of diagnosis of pediatric bipolar disorder has doubled in outpatient settings and quadrupled in hospital settings, and some studies estimate that as many as 2% of youth may have some form of the disorder.

Previously known as manic depression, this diagnosis refers to drastic changes in mood from manic highs to depressive lows. These changes in mood far exceed the normal mood swings children and adolescents will experience in the course of daily life events, and are so extreme that they interfere with daily activities at home and in school.

Currently, the only known effective treatments for pediatric bipolar disorder are family therapy and cognitive behavioral therapy. Family therapy works with the family as a whole to improve the quality of interactions between family members when a child is affected by bipolar disorder. Cognitive behavioral therapy works with the individual to develop skills for coping with the day-to-day problems associated with bipolar disorder.

Although research into pediatric bipolar disorder has seen a substantial increase in recent years, the causes of this disorder - and criteria for its diagnosis - are still not very well-understood. There is still some controversy among psychiatrists over whether pediatric bipolar disorder is the same mental disorder as adult bipolar disorder, and whether the same criteria for diagnosis of adult bipolar disorder should apply in children and adolescents.

Human neural stem cells from fetal cortex stained for DNA (blue), neuronal (green), and astrocyte (red) markers.
Human neural stem cells from fetal cortex stained for DNA (blue), neuronal (green), and astrocyte (red) markers. | Source

Symptoms and Diagnosis

Bipolar disorder includes both depressive symptoms and manic symptoms. Depressive symptoms include extreme irritability, sadness, fatigue, excessive sleeping or insomnia, changes in appetite, and lack of interest in usual activities.

Manic symptoms of this disorder can include racing thoughts, rapid changes in conversation topic, inability to sit still, unusual drive to pursue unrealistic goals, feeling energetic despite a lack of sleep, overinflated self-esteem, and engaging in risky behavior. A subcategory of mania known as hypomania consists of the euphoria, irritability, and energy level of mania, but without the psychotic delusions of grandeur.

In adults, the Diagnostic and Statistical Manual, Fourth Edition, Text Revision(DSM-IV-TR) requires a manic episode lasting seven days or more for a diagnosis of level 1 bipolar disorder. A hypomanic episode lasting four or more days combined with a depressive period is required for a diagnosis of level 2 bipolar disorder.

In children and adolescents, manic and depressive episodes of four to seven days are extremely rare. Cycles can happen daily or multiple times during the day. This difference in the duration of symptoms has led many psychiatrists to advocate using a different standard of diagnosis for pediatric bipolar disorder, and has even led some to speculate that the pediatric form of the disorder may be a different affliction altogether.

Living Through Depression, 2010
Living Through Depression, 2010 | Source

Searching For The Cause

As diagnoses of bipolar disorder in children have increased in recent decades, so has the amount of research into the disorder. This research has looked both at behavioral and biological markers for the disorder that can help psychiatrists standardize the criteria for diagnosis and help researchers try to identify the cause.

Research has found two key behavioral markers for pediatric bipolar disorder. One is a significant difficulty in rapidly switching from one activity to another activity with a different set of rules. This inflexibility in response to a change in situation could point to a misfiring of the ventral prefrontal cortex-striatal-amygdala circuit. This area of the brain controls reward processing in the brain, among other emotional and cognitive functions.

The second key behavioral marker found in a number of studies is a difficulty in reading facial emotions among youths diagnosed with bipolar disorder. Children and adolescents with bipolar disorder are more likely to misinterpret facial expressions than those in a control group, as well as subjects diagnosed with anxiety, depression, or attention deficit hyperactivity disorder. In the studies, subjects diagnosed with bipolar disorder were more likely to identify neutral, emotionless faces as hostile or fear-provoking. These behavioral results also point to anomalies in the amygdala that may be causing the inappropriate response to facial stimuli.

However, attempts to find physical evidence of these anomalies in the ventral prefrontal cortex-striatal-amygdala circuit using magnetic resonance imaging (MRI) have so far found mixed and sometimes conflicting results. A number of structural magnetic resonance imaging (sMRI) studies have found that the overall volume of the amygdala is smaller in youths with pediatric bipolar disorder compared with the control group. Studies comparing volume of the prefrontal cortex, striatum, and other parts of the brain associated with emotional response and reward processing have not shown consistent results, with some studies finding significant differences between subjects with and without bipolar disorder, and others finding no significant difference.

Functional magnetic resonance imaging studies have had even less success in identifying a neurological cause for pediatric bipolar disorder. Some studies have found hyperactivity in the amygdala, striatum, and prefrontal cortex among subjects with pediatric bipolar disorder, while others found diminished activity in the same regions. These differences could be explained by the different methods used in the studies to generate emotional and cognitive responses. Some studies measured responses to neutral, emotionless faces, others measured responses to happy or angry faces, and still others asked subjects to perform memory tasks while their brain activity was being monitored via magnetic resonance imaging.

The best conclusion that can be drawn so far from studies of bipolar disorder in children is that further study is needed. While there is still disagreement among researchers and clinical psychiatrists over how to define and diagnose the disorder, there is bound to be inconsistency in the studies trying to identify the source of the disorder. If the current trend of increasing research into bipolar disorder in children continues, there is hope that some answers may soon be found to explain the cause of this often debilitating disorder.


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    • Teresa Coppens profile image

      Teresa Coppens 5 years ago from Ontario, Canada

      being an adolescent is hard enough without facing these often complicated life experiences while dealing with manic depression or any other form of mental illness. And there is such a stigma attached to mental illness that few seek the help they need to cope effectively. Well written hub on an important topic. Hopefully some definitive answers will be available soon to effectively treat bipolar illness.